Noise-suppressing control lever for vibration prone mechanisms

ABSTRACT

A manually shiftable lever having a free end for manipulation by an operator and an opposite end extending through an opening in a housing where noise may originate includes a sleeve mounted coaxially on the lever by axially spaced resilient rings, and a resilient cover connecting the sleeve to a collar mounted on the housing so that the lever is effectively enclosed by vibration dampening means to minimize the transmission of noise through the lever itself as well as suppressing the passage of airborne noise through the lever opening in the housing.

United States Patent Duncanson et al. Apr. 2, 1974 [54]NOISE-SUPPRESSING CONTROL LEVER 2,272,897 2/1942 Riesing 74/523 FORVIBRATION PRONE MECHANISMS 3,484,808 12/1969 Contemo... 16/121 X3,561,281 2/1971 wllfert 74/523 X Inventors: William a m mJam 3,693,4679/1972 06l'1l 74 473 R C. Kennedy, Jr., Washington, both 3,732,7465/1973 Fitzpatrick 74/523 X of FOREIGN PATENTS OR APPLICATIONS 1 1Assignee! Caterpillar Tractor Peoria, 1,909,s51 9 1970 Germany 74 473 R[22] Filed: July 17, 1972 Primary Examiner-Stephen J. Tomsky [21] Appl.No.: 272,406 Assistant Examiner-John F. Gonzales 1 Attorney, Agent, orFirm-Fryer, Tjensvold, Phillips & 152 U.S. c1. 181/33 A, 16/121, 74/473P, Lempio 74/523, 74/543, 181/33 K [51] Int. Cl G05g 9/00 [57] ABSTRACT[58] Field of Search" 181/33 33 33 33 R; A manually shiftable leverhaving a free end for ma- 74/473 R7 473 543; 287/85 R; nipulation by anoperator and an opposite end extend- 16/121 30 ing through an opening ina housing where noise may originate includes a sleeve mounted coaxiallyon the [56] Reierences C'ted lever by axially spaced resilient rings,and a resilient UNTTED STATES PATENTS cover connecting the sleeve to acollar mounted on 1,848,892 3 1932 Kollmar 16/121 x h ng so that h leveris effectively enclosed y 1,896,893 2/1933 Harts0ck.... 74/473 Pvibration dampening means to minimize the transmis- 1,911,322 33 ay et 7P sion of noise through the lever itself as well as supl,927,646 1 174/473 P pressing the assage of airborne noise through the 2,061,81111/1936 Sinko 16/121 ux lever Opening in the housing. 2,107,204 2/1938Macksey, 16/121 2,199,018 4/1940 Bahr 16/121 7 Claims, 5 Drawing FiguresATENTEflAPR 2:914

SHEEI 2 (If 2 lll MM M V BACKGROUND OF THE INVENTION,

This invention relates to control levers for powered mechanisms such asvehicles and the like and more particularly to means for suppressing therelease of acoustical energy through control levers and associatedstructure.

Recent studies on the sources of noise in vehicle cabs have indicatedthat control levers, such as transmission drive ratio selector levers,often transmit a large volume of sound into the operators environmentalarea. While cabs are frequently lined with accoustical insulatingmaterial, one small opening for airborne sound or only a singlenoise-emitting member can largely defeat the efforts to soundproof thecab. Heretofore, it has been customary to provide a resilient bootbetween control levers and the supporting housing to close the openingthrough which the lever passes. In many instances this has not beenfully successful because vibrations in the audible range are stilltransmitted through metal-to-metal contact from the controlled mechanismto the lever and are radiated from the operator manipulated end of thelever. The problem is aggravated if the levers have a length and massestablishing a natural vibrational frequency similar to the sourcenoises and thus vibrate in resonance with the exciting energy source.The resilient boots heretofore placed around the lower end of suchlevers have insufficient damping qualities to minimize the vibrationaltendencies of many of these problem levers.

SUMMARY AND OBJECTS OF THE INVENTION This invention is a manuallymanipulatable operators control lever construction for mechanisms whichare prone to produce unwanted noise and wherein such noise may tend tobe transmitted through the control lever and through openings providedfor the control lever. Release of acoustical energy is suppressed byenclosing at least a major portion of the operators end of the controllever in a sleeve of greater diameter with resilient support rings beingdisposed between the sleeve and lever. Preferably the sleeve connectsdirectly with a resilient boot which closes the lever opening to blockairborne noise thereat.

Accordingly it is an object of this invention to reduce noise in theoperators area of vibration prone mechanism.

It is another object of the present invention to provide an operatorscontrol lever for vehicles or other vibration prone mechanism which moreeffectively suppresses noise transmission through the lever and as- Ysociated structure.

Other objects and advantages of the present invention will become morereadily apparent upon reference to the accompanying drawings andfollowing descripllOl'l.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of anoise-suppressing lever embodying the present invention,

FIG. 2 is a vertical section view of the lower end of thenoise-suppressing lever taken along line Il--II of FIG. 1,

FIG. 3 is an exploded axial section view of the upper end of thenoise-suppressing lever of FIG. 1,

FIG. 4 is an axial section view of the upper end of a second embodimentof a noise-suppressing lever, and

FIG. 5 is an axial section view of the upper end of a third embodimentof a noise-suppressing lever.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings, andmore particularly to FIGS. 1 and 2 in conjunction, there is illustrateda noise-suppressing selector lever assembly 6 which in this instance isthe drive ratio selector or gear shift member controlling a vehicletransmission. Lever assembly 6 has a slightly tapered control lever 8which extends downwardly from an operator manipulated end 10 to anopposite or lower end 12 and through an opening 14 in a housing 16 andconnects with transmission shifting structure 18 which may be ofconventional design. The control lever 8.is positionable inpredetermined patterns relative to housing 16 to realize differenttransmission settings as well understood in the art. Aflexibleinsulating ring 26 of acoustical polyurethane foam, heavy sheet rubberor the like, is disposed between the lever 8 and opening 14 to suppresspassage of airborne noise through the opening. A cylindrical collar 28is also disposed above the opening and is secured to the housing 16 by aplurality of bolts 30. The outer cylindrical surface 31 of theinsulating ring 26 abuts the inner cylindrical surface 32 of the collar28, and the insulating ring further has an integral upwardly extendingtubular inner portion 33 with an internal opening 34 through which thelever 8 passes. In other instances where a sheet rubber element is usedthe edge thereof may serve as a gasket by extending outwardlyintermediate the flange of the collar and the housing.

The noise-suppressing selector lever assembly 6 further includes anelongated sleeve or cylindrical casing 38 of high mass or high densitymaterial such as lead or steel which generally encircles the controllever 8 in spaced relation therefrom. This sleeve 38 is held in place onthe lever 8 by a plurality of axially spaced resilient rings 40 ofrubber or other elastomeric material. As best shown in the exploded viewof Figure 3, the upper end of the sleeve is provided with an integralannular cap 42 in which is mounted a resilient annular elastomericmember 44 having an upper cylindrical extension 45 that fits within anopening 46 in the cap. A thrust washer 47 is welded or otherwise securedto the lever 8 to retain the upper end of the sleeve thereat.

The operator manipulated end 10 of the lever assembly 6 consists of agrippable knob 48 secured to an upper threaded end 50 of the controllever 8, which projects above member 44, through an intermediateresilient mount 52. This resilient mount 52 is of molded rubber or otherelastomeric construction and contains an internally threaded lowerinsert 54 at the lower face and an upper insert 56 that includes athreaded stud 58 extending above the upper face. The knob 48 is providedwith an internally threaded bore 60 and is threaded on the stud 58 ofthe resilient mounted insert 56. The lower insert 54 of the resilientmount is threadably engaged on lever end 50 with the lower face of themount abutting the cap 42.

Referring again to Figure 2, the lower portion 12 of the lever assembly6 includes a molded resilient boot 62 mounted on an upper flaredperipheral lip 63 of the collar 28 by disposition of the lip in are-entrant rim 64 of the boot. This boot 62 also has anupwardlyextending tubular portion 66 encircling the lower end and thecontrol lever 8. Second, there are airborne vibrations which would passoutwardly through any opening in the housing 16 unless a suitableclosure member is provided. Vibrations transmitted directly through thecontrol lever 8 are effectively suppressed by the above described highdensity sleeve 38, and resilient rings 40 which jointly have anoise-dampening effect. Vibrations transmitted by the control lever 8 donot couple strongly to the surrounding air nor readily pass upwardly tothe operator manipulated end 10 through the resilient rings 40 and thesleeve 38 which act as an acoustical shield and as a dampening means.Still another noise suppressing effect may be operative in thoseinstances where a control lever 8, lacking the present invention,exhibits a natural frequency of vibration which is in resonance withthat of the exciting energy source and therefore tends to vibrate verystrongly. In such instances, the additional mass provided by theelements of the present invention may shift the natural frequency of thelever away from resonance with the vibration source.

In connection with airborne noise suppression, the present inventionprovides a dual noise barrier. The insulating ring 26 provides a firstsuch barrier, while the boot 62 and lower resilient ring 40 provide thesecond barrier. In addition, both the resilient extension 33 of the ring26 and the upwardly-extending tubular portion 66 of the boot 62 tend todirectly dampen direct vibration of control lever 8. 7

Noise emission from the operator manipulated end of the lever assemblyis still further reduced by the resilient mount 52 intermediate the knob48 and the lever 8. The resilient mount 52 further attenuates directvibration transmission from the control lever 8 to the knob 48.

FIG. 4 shows a second embodiment of the noisesuppressing selector leverassembly 6 which may be similar to that previously described except fora modified operator-manipulated end 10. In this embodiment a resilientelastomeric ring 72 is disposed on the upper end of the control lever 8between a pair of rigid washers 74. A nut 76 is threadably engaged onthe upper threaded end 50 of the control lever 8 for urging the upperwasher 74 downwardly to compressibly load the ring 72. Sleeve 38' inthis embodiment is modified to have an annular band portion 78 ofarcuate cross section to receive and retain ring 72 which isradiallyexpanded by turning nut 76. An internally threaded cap 80 issecured to the intermediate resilient mount 52 by a bolt 82, and isthreadably engaged on external threads 83 on the upper end of the sleeve38'.

In the second embodiment of the invention shown in FIG. 4, the. upperend of the control lever 8 is more fully isolated from the resilientmount 52 than in the first described embodiment as twovibration-inhibiting barriers 72 and 52 are present between lever 8 andknob 48.

Another modification of the operator manipulated end 10 of the leverassembly is shown in FIG. 5 wherein the knob 48 is coupled to the upperend of sleeve 38" through an adapter cup 86 and an intermediateextension tube 88. The extension tube 88 has internal threads 90 on thelower end thereof which threadably engage external threads 92 on theupper end of the sleeve 38". Similarly, the adapter cup 86 has internalthreads 94 which engage external threads 96 on the tube. Theintermediate extension tube fits around the uppermost ring 40 and aresilient grommet 98 which is disposed coaxially on control lever 8above the ring 40. A washer 74 is situated between uppermost ring 40 andgrommet 98 and these three elements are held in position by an inwardlyextending lip ,100 of tube 88. Within cup 86, a larger diameterresilient grommet 102 is disposed coaxially on lever 8 and a nut 76 andadditional washer 74 serve to secure the upper grommet in place.

The third embodiment of the invention shown in FIG. 5 situates the knob48 in metal-to-metal communication with the sleeve 38" through theadpater cup 86 and the extensiontube 88. This provides a somewhat firmercontrol or kinesthetic feel to the operator, while still providingvibration inhibiting elements between the control lever 8 and exposedexternal surfaces of the assembly.

While the invention has been described and shown with particularreference to certain preferred embodiments, it will be apparentthatother variations are possible within the scope of the invention, whichis not intended to be limited except as defined in the following claims.

What is claimed is:

l. A noise-suppressing lever assembly for manually controlling avibration prone mechanism, said lever assembly having an operatormanipulated end and an opposite end extending through an opening in ahousing containing said mechanism comprising:

a pivotable control lever having a first end extending into said housingthrough said opening and being coupled to said mechanism therein,

a rigid knob grippable by an operator and coupled to the second end ofsaid lever through vibration dampening means,

an elongated sleeve encircling said control lever in radially spacedrelation thereto and enclosing substantially the entire length of saidlever between said housing and said knob,

annular resilient mounting means disposed coaxially between saidelongated sleeve and said control lever for supporting said sleevethereon while inhibiting transmission of vibration from said controllever to said sleeve, and

a flexible boot extending between said sleeve and said housing at saidopening to inhibit transmission of airborne noise therethrough.

2. The noise-suppressing lever assembly of claim 1 wherein saidelongated sleeve is formed of rigid material which is denser than thematerial of said sleeve mounting means.

3. The noise-suppressing lever assembly of claim 1 wherein saidresilient mounting means comprises a plurality of axially spaced apartelastomeric ring members.

4. The noise-suppressing lever assembly of claim 1, wherein said knob isattached to said elongated sleeve through a resilient mount for furtherinhibiting transmission of vibration to said control knob.

5. The noise-suppressing lever assembly of claim 4 wherein saidresilient mount is secured to said sleeve independently of said controllever.

6. The noise-suppressing lever assembly of claim 1 6 7. Thenoise-suppressing lever assembly of claim 1 further comprising a ringformed of acoustically absorbant material extending between said leverand said wherein said knob is secured to said sleeve by rigid 5 openingin Spaced relation from Said bootmeans.

1. A noise-suppressing lever assembly for manually controlling avibration prone mechanism, said lever assembly having an operatormanipulated end and an opposite end extending through an opening in ahousing containing said mechanism comprising: a pivotable control leverhaving a first end extending into said housing through said opening andbeing coupled to said mechanism therein, a rigid knob grippable by anoperator and coupled to the second end of said lever through vibrationdampening means, an elongated sleeve encircling said control lever inradially spaced relation thereto and enclosing substantially the entirelength of said lever between said housing and said knob, annularresilient mounting means disposed coaxially between said elongatedsleeve and said control lever for supporting said sleeve thereon whileinhibiting transmission of vibration from said control lever to saidsleeve, and a flexible boot extending between said sleeve and saidhousing at said opening to inhibit transmission of airborne noisetherethrough.
 2. The noise-suppressing lever assembly of claim 1 whereinsaid elongated sleeve is formed of rigid material which is denser thanthe material of said sleeve mounting means.
 3. The noise-suppressinglever assembly of claim 1 wherein said resilient mounting meanscomprises a plurality of axially spaced apart elastomeric ring members.4. The noise-suppressing lever assembly of claim 1, wherein said knob isattached to said elongated sleeve through a resilient mount for furtherinhibiting transmission of vibration to said control knob.
 5. Thenoise-suppressing lever assembly of claim 4 wherein said resilient mountis secured to said sleeve independently of said control lever.
 6. Thenoise-suppressing lever assembly of claim 1 wherein said knob is securedto said sleeve by rigid means.
 7. The noise-suppressing lever assemblyof claim 1 further comprising a ring formed of acoustically absorbantmaterial extending between said lever and said opening in spacedrelation from said boot.